In addition to heavily doped semiconductors, the disordered conducting media exhibiting activated hopping transport at \(\alpha \)  that differs from the “classical” values \(\alpha \)  = 1/4 and 1/3 (or 1/2) are mainly carbon-containing systems of various structures [1]}, [2]}, [3]}, [4]}, [5]}, conducting
polymers [6]}, [7]}, [8]}, and polycrystalline
graphene [9]}.The case \(\alpha \)  = 1/2 is known to be not only a one-dimensional version of Eq. (REF ), but above all to be the result of appearance of a Coulomb gap near the Fermi level due to electron-electron interaction regardless of the dimensionality (Shklovskii-Efros law [10]}).
For example, \(\alpha \)  in carbon black (CB)-polymer composite systems ranges from 0.5 to 0.79 [1]}, [2]}, [5]}, which was explained in terms of the model of electronic state superlocalization in a fractal structure [14]}, [15]}. According to the results of studying the hopping conduction in polycrystalline graphene [9]}, specific values \(\alpha \)  = 0.41 and 0.72 were observed along with the value (\(\alpha \)  = 0.33) characteristic of 2D systems. The authors [9]} suggest that, although graphene is a 2D system, conduction in this case occurs via jumping between conducting crystallite boundaries, and its behavior was interpreted using a quasi-one-dimensional model [18]}.
